US2894373A - Method for storing and shipping foodstuffs and the like - Google Patents

Description

July 14, 1959 W. L. MORRISON METHOD FOR STORING'AND SHIPPING F OODSTUFFS AND THE LIKE Filed Feb. 20, 1956 4 Sheets-Sheet 1 INVEN TOR. WILLARD L .M ORRISON BY PARKER 8- CARTER ATTORNEYS W. L. MORRISON July 14, 1959 METHOD FOR STORING AND SHIPPING FOODSTUFFS AND THE LIKE Filed Feb. 20, 1956 4 Sheets-Sheet 2 (ll. Ill 7 INVENTOR. WILLARD LMORRISON BY PARKER 8-CARTER ATTORNEYS y 14, 9 w. MORRISON I 2,894,373

METHOD FOR STORING AND SHIPPING FOODSTUFFS AND THE LIKE Filed Feb. 20, 1956 I 4 Sheets-Sheet 3 Zga IN VEN TOR.

WILLARD L.MORRISON- BY PARKER &CARTER ATTORNEYS July 14, 1959 w. MORRISON METHOD FOR STORING AND SHIPPING FOODSTUFFS AND THE LIKE Filed Feb. 20, 1956 4 Sheets-Sheet 4 INVENTQR. WILLARD L. MORRISON .BY PARKER 8. CARTER ATTORNEYS United States Patent METHOD FOR STORING AND SHIPPING FOODSTUFFS AND THE LIKE Willard L. Morrison, Lake Forest, 111., assignor to The Union Stock Yard and Transit Company of Chicago, Chicago, 111., a corporation of Illinois ApplicationFebruary 20, 1956, Serial No. 566,477

6 Claims. (CI. 62-64) My invention relates to method and apparatus for storing and shipping perishable materials such as foodstuffs and the like.

One object of my invention is to make it possible to safely store and ship perishable materials without cooling between the time when the materials are initially chilled for shipment and storage and the time perhaps many days later when the container in which the materials are stored and shipped is opened for disposal of the contents.

Another object of my invention is to pack and chill the material in such wise that when the chilling has been completed, there will be substantial temperature variation Within the mass, those parts most exposed to ambient heat being at a temperature much lower than the remainder so that as ambient heat enters through the insulated walls of the container, differential temperature rise will occur and the temperature will approach if not actually reach uniformity at the time when the container is to be opened, with the warmest part of the mass still below the safety point.

.I propose to cool or 'superchill such materials to a very low temperature, perhaps several hundreds of degrees below zero degrees F. while they are enclosed in an insulated storage box or shipper container. Such materials have relatively low heat conductivity and as heat penetrates, the temperature of the outer or exposed layers of the material will rise more rapidly than that of the remainder of the mass.

When the insulated filled container is closed after the contents have been superchillecl, the temeprature of the mass must be so low that inflow of heat through the insulation in the absence of any further cooling will be unable to raise the warmest part of the contents during the time of shipment and storage to the danger point which is preferably below zero degrees F.

The outer layers of the mass tend to receive heat and rise in temperature more rapidly than the inner layers. Different parts of the outer layers may receive heat at different rates. If the shipper container is deck load on aboat'or exposed on a railroad car with the sun beating down upon it, the top layer Will receive more heat than the side and bottom. Since each of the eight corners of the mass, assuming it to be rectangular are exposed on three sides, the corners will receive heat through three surfaces. The sides will receive heat through but one surface. The vertical corners will receive heat through two surfaces.

Cooling is expensive, and it is uneconomical to cool those parts of the mass less exposed to heat to a temperature as low as those parts more exposed to heat. Therefore, I propose to cool the mass dilferentially. Under some circumstances the top layers will be colder than the remainder of the mass. Under other circumstances, the outer layers, top, bottom and sides may be colder than the remainder of the mass. Under other circumstances the eight pyramidal corners of the mass ice will tend toward, though not necessarily ever reachingv uniform temperature throughout.

The size of the container, the thickness or effectiveness of the insulation and the initial diiferential temperatures of the various parts of the mass depend on the time and conditions of storage and shipment. If the container is to be shipped for long distances or stored for a long time, or exposed to extreme heat, the temperatures may be very low, in the order perhaps of several hundred degrees below zero degrees F. On the other hand, if the storage time or the shipment distance is short, or the ambient temperatures low, the starting temperatures may be higher. It is essential that when the box is opened at the end of its trip or at the end of its storage time, no refrigeration having been provided between the initial cooling and the time of opening, the temperature of the entire contents of the box be below the danger line. The relationship between the temepratures of the relatively colder and relatively warm parts of the contents of the container must be sufficient to insure that at the end of shipment or storage all of the contents is below the danger line and little if any of the contents is needlessly below the danger line. If the box reaches its destination with the warmest part of its contents at -10 degrees F. and other parts at -50 degrees F., time and money have been wasted in needlessly chilling part of the contents.

If the entire contents is uniformly chilled to a point such that the warmest part, the part that rises in temperature most rapidly is safely below the danger zone while a large part of the box contents is needlessly far below the danger zone, time and money will have been wasted without adding anything to the safety of ship-' ment and storage.

I propose, for example, to pack the container full of packages of frozen foodstuffs from one of the conventional commercial food freezing plants. The frozen packages may be separate or may be assembled in cartons. In either case, they are self-supporting and there will always be some clearance between and about them, I will then chill the contents of the container far below the freezing temperature by discharging for example liquid nitrogen, liquid air or other cold boiling liquid at atmospheric pressure and temperature several hundred degrees below zero degrees F. into the container. The liquid will penetrate the clearances between the packages, and being in close contract with them will absorb heat from the packages, will be boiled or vaporized and will leave the container as gas. This will continue until the temperature of the contents has been lowered to the desired points. A cold gas might be used though cooling by the latent heat of vaporization of the liquid is preferable.

The differential cooling above referred to may be ac complished by packing the corners of the mass more loosely so that more liquid will flow down around the corners than throughout the remainder of the contents or ducts may be used to conduct the liquid to the corners and sides of the mass so that the coolant first contacts those parts of the mass needing the lower temperature.

Another possible solution of the problem is to interpose a blanket of absorbent material between the upper and lower layers so that the liquid cannot reach the lower layers until the blanket has been saturated while the upper layers are in earlier contact with the liquid.

If a more or less impervious horizontally disposed partin-g sheet, terminating short of the container walls-andr additionally cut away at the corners is interposed between the main body of the packages and the upper layer or two of the container and if the cold boiling liquid is then poured onto the top layers, it will travel down through the clearances to the parting sheet, will migrate outwardly toward the outer layers in the container, will contact those layers first, will then travel downwardly and of course also inwardly to cool the central body of the mass to a less extent that the cooling of the top and side layers and since the cutting away of the corners of the mass to a less extent than the cooling of the top the corners also will be differentially cooled so that when the most exposed portions of the mass have reached the desired minimum temperature, supply of the liquid will cease, the container will be closed, ready for storage and shipment with differential temperature conditions.

One of the advantages of using nitrogen or other cold boiling liquid which will not deleteriously affect the foodstuffs is that the usual inexpensive wrapping of canvas is sufficient, there being no objection to contact of the liquid with the food.

My invention is illustrated more or less diagrammatically in the accompanying drawings, wherein- Figure 1 is a vertical section through a container embodying my invention;

Figure 2 is a similar section showing a modified arrangement;

Figure 3 is a horizontal section through the device of Figure 2 before the upper layers of packages have been installed;

Figure 4 is a section similar to Figure 1 illustrating a different method of applying the liquid.

Like parts are indicated by like characters throughout the specification and drawings.

The space between the outer wall 1 and the inner wall 2 of a shipper container is filled with an insulating mass 3. The details of support for the inner and outer walls and the insulating mass form no part of the present invention and are not here illustrated. A removable insulating mat 4 rests upon the mass of material in the container and S is a cover for the container resting on the outer walls 1 and insulated from the inner walls and from the contents by the mat 4-. A multiplicity of packages of foodstuffs 6 is illustrated with the clearance 7 between them. An absorbent mattress 8 is interposed between the main body of material and the upper layers 9. Any suitable means may be used for supplying the cold boiling liquid to the top layers 9 of the shipper container contents. Such liquid will pass down through the clearance between the packages, will saturate the mattress 8 and thereafter pass downwardly in contact with the food bodies 6. By this arrangement, the upper layers will be first cooled, will be longer in contact with the cold boiling liquid and will be of lower temperature than the upper layers.

The device of Figures 2 and 3 is similar to that of Figure 1 except that a parting sheet It? is substituted for the mattress 8. The parting sheet is horizontally disposed. It stops short of the inner walls of the container and is cut away at the corners, thus separating the upper and lower layers just as did the mattress 8. When the cold boiling liquid is supplied to the upper layers to pass down through the clearance, its downward travel is prevented by the parting sheet 10, the liquid travels o-utwardly and flows off the edges of the parting sheet into contact with the lower layers and since the sheet is cut away at the corners, more liquid will be discharged there than at the sides. Again the upper layers and the side and corner layers will receive the liquid earlier and in greater quantity and that liquid will finally penetrate sufficiently throughout the mass to cool the central portion to as low a temperature as the upper side and corner layers.

A supply duct 11 is provided for the cold boiling liquid. Branches 12 extend laterally from the duct to discharge the cold boiling liquid at the corners and sides of the mass as indicated so that the corners and sides of the mass receive earlier larger quantities of the cold boiling liquid and so are cooled to lower temperatures than the remainder of the mass.

While nitrogen is a preferred coolant, it is obvious that other cold boiling liquids which boil at atmospheric pressure and temperature far below zero could equally well be used. While I have referred for illustration to particular temperatures below zero degrees, it will be understood that the invention does not lie in particular temperatures but in the differential temperature control which makes it possible to produce the new result.

I claim:

1. The method of storing foodstufis for a predetermined time period which includes packing a mass of separate packages of frozen food, at temperatures in the order of zero degrees F. in an insulating zone, then while cooling the entire mass below zero degrees F. differentially cooling, those parts of the mass more exposed to heat infiltration, to temperatures below the temperatures of those less exposed and controlling such differential temperatures in consonance with the expected time of storage and rate of heat infiltration so that at the end of the time period, the temperature of the entire mass will be substantially uniform and in the order of zero degrees F.

2. The method of storing foodstuffs for a predetermined time period which includes packing a mass of separate packages of frozen food, at temperatures in the order of zero degrees F. in an insulating zone, then while cooling the entire mass below zero degrees F. differentially cooling the various parts of the mass to temperatures in consonance with their exposure to heat infiltration and controlling such differential temperatures in consonance with the expected time of storage and rate of heat infiltration so that at the end of the time period, the temperature of the entire mass will be substantially uniform and in the order of zero degrees F.

3. The method of storing foodstuffs for a predetermined time period which includes packing a mass of separate packages of frozen food, at temperatures in the order of zero degrees F. in an insulating zone, then discharging a cold boiling liquid into the zone at substantially atmospheric pressure and at temperature in the order of 230 degrees F. to cool the entire mass below zero degrees F. and distributing the liquid with respect to the mass to differentially cool those parts of the mass more exposed to heat infiltration to temperatures below the temperatures of those parts less exposed until such differential temperatures, in consonance with the expected time of storage and rate of heat infiltration, are such that at the end of the time period, the temperature of the entire mass will be substantially uniform in the order of zero degrees F.

4. The method of storing foodstuffs for a predetermined time period which includes packing a mass of separate packages of frozen food, at temperatures in the order of zero degrees F. in an insulating zone, then discharging a cold boiling liquid into the zone at substantially atmospheric pressure and at temperature far below zero degrees F. to cool the entire mass below zero degrees F. and distributing the liquid with respect to the mass to differentially cool those parts of the mass more exposed to heat infiltration to temperatures below the temperatures of those parts less exposed until such differential temperatures, in consonance with the expected time of storage and rate of heat infiltration, are such that at the end of the time period, the temperature of the entire mass will be substantially uniform.

5. The method of storing foodstuffs for a predetermined time period which includes packing a mass of separate packages of frozen foodstuffs in an insulating zone, closing the zone to exclude ambient air, discharging into the zone a supply of a cold boiling liquid at substantially atmospheric pressure and temperature far 5 below freezing and directing the flow of such liquid against selected portions of the mass in the zone to differentially cool such portions and continuing such diiferential cooling until the temperatures of the mass, while remaining different, are all far below zero degrees F.

6. The method of storing foodstufis for a predetermined time period which includes packing a mass of separate packages of frozen foodstufls in an insulating zone, closing the zone to exclude ambient air, discharging into the zone a supply of a cold boiling liquid at substantially atmospheric pressure and temperature far below freezing and directing the flow of such liquid against selected portions of the mass in the zone to differentially cool such portions and continuing such differential cooling until the temperatures of the mass, while remaining different, are all far below zero degrees F., and until the temperatures of the mass in consonance to their expected temperature rise as a result of heat infiltration into the zone are such that at the end of the predetermined time, the temperature of the entire mass will be substantially constant.

References Cited in the file of this patent UNITED STATES PATENTS 2,479,867 Rosebaugh Aug. 23, 1949 2,483,100 Morrison Sept. 27, 1949 2,618,939 Morrison Nov. 25, 1952

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